Abbreviations:
ICU = Intensive Care Unit, IPD = Indoor Patient Department, SpO2 = Peripheral capillary oxygen saturation, HFNC = High flow nasal cannula, FiO2 = fraction of inspired oxygen, HRCT = High-resolution computed tomography, ARDS = acute respiratory distress syndrome, DGHS = Directorate General of Health Services, NRBM = non-rebreather mask, BP = Blood Pressure, mmHg = millimetres of mercury, RR = Respiratory rate, NIV = Non-invasive ventilation, ABG = Arterial blood gas, CSS = Churg-Strauss syndrome, LDH = Lactate dehydrogenase, INR = International normalized ratio, ECG = Electrocardiogram, CRP = C-reactive protein, RBS = Random blood sugar, ESR = Erythrocyte sedimentation rate, BNP = brain natriuretic peptide.